IMO, probably is an error. I booked seat 30D for a few times, it is actually a front row seat and a seat next to the exit door, which should be considered as an exit row as well. 31A and C indeed are exit row seats. 31D/E/F/G are no difference comparing to other Comfort + seats, as the IFE is located in front of the seat. H/K seats starts from 32 due to the horrible WC located next to rows 30 & 31.

Little bit more detail on the comfort + seats experience:
- Legroom is definitely better than the cramped Economy seats.
- Be the first to disembark. Even though there is little difference when arriving HKG, as the bags usually arrive very slowly. It can make a difference when arriving in DOH, especially this aircraft type has a high chance to arrive on a remote stand. Be the first on the bus, you can get a seat for the 10-20 mins bus ride, and arrive to the terminal earlier than those sitting in the middle cabin and sometimes rear cabin.
* Depends on bus availability and other factors, there are chances that the rear doors will be used for disembarking at the same time.
- The IFE in comfort + seats are extremely lag, and sometimes turned in black screen.
- Expect to be a poor maintained aircraft and seat. I had once when the edge of partition separating Business Class & Comfort + is not glued, which could be a tripping hazard for customers. I had also came across faulty seats, which IFE is not operating, as well as not able to fold away the front row IFE before landing.
- Think very carefully before choosing seats 30D/E/F/G. As this is a front row seat, there are lots of people trying to get through for the WC, which is extremely rude and lack of respect. Customers on the left aisle are supposed to use the WC between rows 59 and 69, not turning around in Business Class or passing through seats 30D/E/F/G. I do experienced when a customer fell towards me, also tripped by my charging cable while passing through 4 seats.
- Once a customer opens the WC door in Comfort + cabin, the cabin just literally lit. This particularly affect customers in rows 30 and 31.
- Due to the horrible blind setting, customers sitting in seat 30D and 30G will be affected when the aircraft reaches 10000 ft after take off, as well as cabin crew constantly passing through between cabins. You can feel that when they are moving the blind, which could be disturbed while you are sleeping.
- Seats 31A/C are exit row seats as mentioned above, be aware that cabin crew will sit in front and facing each other during take off, landing and strong turbulence.

I would recommend (if options available), to choose row 33. If you are unfortunately being allocated seats 30D/E/F/G, there is a way that can mitigate the disturbance from those passengers:
- Try to maximise the recline, open the foot rest and put the backpack / laptop bag (if you have one) after seat belt sign has switched off after reaching cruising level.
- This has to be done by all 4 seats in front row.
- Once the customers see there are lack of space they can pass through, they will walk away.

Hope that's useful for HKG, MLE & IST travellers.